Mr. Rittenhouse was among those, who early yielded to the call of their fellow-citizens to serve them in a civil capacity. Dr. Franklin and Major (afterwards General) Mifflin had been respectively appointed by the continental congress, in the year 1775, to be post-master general of “the United Colonies of North-America,” and quartermaster-general of the American army: and, in consequence of these appointments, both these gentlemen resigned, in the early part of the ensuing year, the seats they had occupied in the general assembly of Pennsylvania, as burgesses for the city of Philadelphia. To supply this vacancy in the representation of that city, Colonel (afterwards General) Joseph Reed and David Rittenhouse, Esq. were elected, in March 1776. Mr. Rittenhouse took his seat on the 5th day of the same month, and continued an useful member of that body until the termination of its legislative functions. But, although he was a valuable and highly respectable member of that house, he did not possess that species of talent which often enables a man of even moderate abilities, to make a prominent figure in popular assemblies: his perception was extremely quick; in deliberative powers he excelled; and all his reasoning faculties were most accurate: yet, an insuperable native diffidence—pursuits which precluded opportunities of public speaking—and, perhaps, a peculiar structure of his mind—all forbad his being an orator. Notwithstanding the agitating and highly important public events which occupied men’s minds, in the memorable year 1776, Mr. Rittenhouse could not entirely abandon, even then, his darling pursuits. His ardent attachment to the Newtonian philosophy led him, on various occasions, to vindicate it against new-fangled theories which sometimes appeared against it: for there still remained a few speculative men, and, among these, some persons of considerable learning, who continued to adhere to the visionary principles of Descartes and his followers.[180] Of this, an instance occurred in the year 1776. A writer under the signature of M. W. (and who is supposed to have been the late Rev. Matthew Wilson, a respectable presbyterian clergyman, of Lewes,[181] in the county of Sussex on Delaware,) published in _The Pennsylvania Magazine_, for March and April in that year, (conducted by the late Mr. Robert Aitken of Philadelphia,) some speculations, under the head of “A proposal for reducing Natural Philosophy to a System, with Remarks on the Cartesian and Newtonian Theories.” In his lucubrations, this writer discovered a decided partiality for the doctrine of Descartes, in preference to those of Newton. Nor did this admirer of the justly exploded philosophy of the former long want a coadjutor: for, in the same Magazine, for the succeeding month, appeared another reverend gentleman of the same religious persuasion, and known to possess a copious fund of scholastic learning; who, under the signature of J. W. approved, in the main, of